Method for identifying a manually actuated steering device and apparatus for performing the method

Abstract

The invention provides a method for detecting a contact with a manually actuated steering device, in particular a vehicle steering wheel, comprising the following steps: applying an alternating voltage to at least one conductor arrangement (10), which is arranged on the steering device and has at least one conductor bundle with a significant ohmic resistance; determining a current curve in the conductor arrangement (10); determining the real part and the imaginary part of the instantaneous alternating resistance of the conductor arrangement (10); determining the capacitance or capacitance change of the conductor arrangement (10); determining a phase shift; and analyzing the determined values. A device for performing the method comprises: a steering device, in particular a vehicle steering wheel; a conductor arrangement (10) arranged on the steering device, which has at least one conductor bundle with a significant ohmic resistance; and a control and analysis device, which is configured to: apply an alternating voltage to the conductor arrangement (10); measure the current curve in the conductor arrangement (10); and analyze the determined values.

Description

Technical Field

[0001] The invention relates to a method for detecting a touch on a manually actuated steering device, in particular a vehicle steering wheel, and also to a device for carrying out the method. Background Art

[0002] Knowing whether the driver of a vehicle is touching the steering wheel is essential or at least useful information for various safety assistance systems and driver assistance systems. In principle, there are various technical possibilities for how to detect touching the steering wheel. In particular, devices are known in which capacitive or resistive sensors are integrated into the steering wheel.

[0003] However, for certain demanding applications, in addition to simple contact detection, it is also necessary to locate the contact, that is, not only the contact with the steering wheel itself must be determined, but also the position of the contact with the steering wheel. However, such position determination is technically difficult to achieve. Additional lines and components are generally required for this purpose, and the assembly effort is significantly increased.

[0004] DE 10 2014 016 422 A1 discloses a device and a method for detecting a contact with a steering wheel, the basis of which is that a first electrode arranged in the steering wheel together with a human body serving as a second electrode and a dielectric located therebetween forms a sensing capacitor. An evaluation circuit having a charged reference capacitor with a known capacitance can be connected in parallel with this sensing capacitor, so that a portion of the charge of the reference capacitor is transferred to the sensing capacitor. Taking into account the known capacitance of the reference capacitor and the voltage measured at the reference capacitor before and after the parallel connection of the evaluation circuit, the change in capacitance of the sensing capacitor required for the detection is determined. If a plurality of first electrodes are provided, which are arranged distributedly on the steering wheel rim and are galvanically isolated from one another, conclusions can be drawn about the specific position of the contact with the steering wheel. Summary of the invention

[0005] The object of the present invention is to be able to detect the position of a contact with a steering device precisely using a simple method.

[0006] This object is achieved by a method for detecting a touch on a manually actuated steering device and a device for carrying out the method. Advantageous and expedient embodiments of the method according to the invention and of the device according to the invention are given in the associated dependent claims.

[0007] The method according to the invention for detecting a touch on a manually actuated steering device, in particular a vehicle steering wheel, comprises the following steps:

[0008] - applying an alternating voltage to at least one conductor arrangement which is arranged on the deflection device and has at least one conductor bundle with a significant ohmic resistance;

[0009] - determining the current curve in the conductor arrangement;

[0010] - determining the real and imaginary parts of the AC resistance of the conductor arrangement;

[0011] - determining the capacitance or the change in capacitance of the conductor means;

[0012] - Determine the phase shift (phase angle); and

[0013] - Analyze the determined values.

[0014] Generally, "determining" shall include measuring, calculating, otherwise determining or knowing a variable.

[0015] The present invention is based on the following recognition, that is, in capacitive measurement technology, there are already established, effective methods for identifying capacitance changes. The first basic method is based on the change of the capacitive coupling of the sensing structure relative to the reference electrode due to the action. The second basic method is based on the change of the capacitive coupling of the sensing structure relative to the surrounding environment due to the action. The present invention expands these methods by taking into account the obvious resistance of the conductor bundle of the conductor structure. That is, according to the present invention, at least one conductor bundle of the conductor structure has a significant ohmic resistance compared to conventional copper wire lines, for example. In this way, an RC component that can be changed and analyzed by action (such as hand contact) is formed. When the applied alternating voltage is known, the total resistance (impedance) of the conductor structure is determined by measuring the current curve. Here, the term "alternating voltage" should include all voltage curves based on oscillations (especially sinusoidal oscillations, rectangular oscillations, triangular oscillations, sawtooth oscillations), but also includes pulse voltages with continuous voltage pulses. Because the total resistance of the conductor structure is composed of the real part determined by the ohmic resistance of the conductor bundle and the imaginary part determined by the capacitance formed between another conductor bundle (reference electrode) or the surrounding environment, the contact position of the steering device can be inferred from the phase angle.

[0016] By cleverly arranging and designing the conductor arrangement, not only can precise position determination be achieved, but also movement patterns (gestures) can be recognized and analyzed in principle. After a successful interpretation, the function assigned to one of the respectively identified gestures can be triggered.

[0017] Since the core of the invention lies in the variable to be measured or determined easily in the analysis and, compared to other contact recognition devices, only a conductor bundle with a significant ohmic resistance is required as the only special component in addition to a small number of regular lines, the invention has the advantage that it is generally cost-effective and can be installed without great effort.

[0018] The steps of the method according to the invention are preferably carried out continuously. This means that the steering device is permanently monitored without long interruptions. This is a prerequisite for reliable posture recognition.

[0019] In the method according to the invention, the analysis of the determined values ​​additionally comprises in particular at least one of the following steps:

[0020] - detecting whether the steering device is touched over a large area;

[0021] - detecting whether the steering device is contacted in a point-wise manner;

[0022] - Identify the grip (the way of gripping);

[0023] - Identify the number of simultaneous contacts;

[0024] - Locate the locations of multiple contacts;

[0025] - Determine the duration of the contact;

[0026] -Logo gesture.

[0027] The more of these steps are performed, the more areas in which the method according to the invention can be applied.

[0028] Due to the possibility of a multifaceted analysis of the determined values, the method according to the invention can be used to trigger specific functions as a function of the analysis.

[0029] The invention further provides a device for carrying out the method according to the invention. The device comprises a steering device, in particular a vehicle steering wheel, a conductor arrangement arranged on the steering device, the conductor arrangement having at least one conductor bundle with a significant ohmic resistance, and a control and analysis device arranged nearby. The control and analysis device is configured to: apply an alternating voltage to the conductor arrangement; measure the current curve in the conductor arrangement; and analyze the determined values. In addition, the control and analysis device is networked with a higher-level control unit of the vehicle, in particular of the onboard electronics.

[0030] In this case, an “alternating voltage” is therefore to be understood generally as a voltage curve based on oscillations (in particular sinusoidal oscillations, rectangular oscillations, triangular oscillations, sawtooth oscillations), but also as a pulsed voltage with continuous voltage pulses.

[0031] The provision of a plurality of conductor means distributedly arranged on the steering device allows, on the one hand, a higher reliability and / or precision (resolution) in contact recognition. On the other hand, it also allows recognition of multi-touch inputs in a manner similar to a touch-sensitive display.

[0032] The conductor arrangement proposed according to the invention is preferably arranged below the surface of the steering device, in particular below the decorative surface. In the case of a vehicle steering wheel, this may be, for example, below the covering of the steering wheel rim. In principle, the conductor arrangement should be placed as close to the surface as possible in order to ensure high sensitivity.

[0033] According to a preferred first embodiment of the device according to the invention, the conductor arrangement has two electrical conductors extending substantially in parallel, at least one of the two electrical conductors having a significantly higher ohmic resistance than a copper wire, preferably in the range of 10Ω / m to 1MΩ / m. In this embodiment, the capacitive coupling of the two conductors changes when a hand is present. By taking into account the determined total resistance, the position of the hand can then be determined.

[0034] In order to prevent undesired coupling or interference with adjacent components from occurring, the electrical conductors should each be insulated.

[0035] According to a preferred second embodiment of the device of the present invention, the conductor mechanism has a plurality of sensing areas in the form of conductive surfaces or conductive areas, which are connected in series with each other by electrical conductors, wherein the electrical conductors have a significant ohmic resistance between the sensing surfaces or sensing areas. Therefore, the conductor mechanism is formed by a series of resistors and conductor surfaces or conductor areas connected in series with each other. In combination with the hand, a characteristic RC component is produced, the behavior of which can be analyzed by a control and analysis device in such a way that the position of the hand can be determined. The reliability and accuracy of contact recognition can be optimized by the number, shape, size and arrangement of the sensing areas or sensing areas. In order to keep the cost of the device low, it is preferred that the conductor mechanism is cleverly arranged and designed so that as few sensing surfaces or sensing areas as possible should be installed and as few cables or conductor circuits as possible should be laid.

[0036] According to another preferred aspect of the invention, the conductor bundle has one or more elongated electrical conductors with a significant ohmic resistance, which are laid out in a specific manner so as to form RC components which can be analyzed in turn.

[0037] In general, due to the already mentioned multifaceted analysis possibilities, it is possible to configure the control and analysis device to be able to trigger specific functions depending on the analysis. In this case, the device serves as a complex command input device, by means of which the operator can specifically call up specific functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Further features and advantages of the invention are apparent from and are made with reference to the following description and drawings. In the drawings:

[0039] - Figure 1 A first embodiment of a conductor arrangement for a device according to the invention for detecting a contact with a manually actuated steering device is shown;

[0040] - Figure 2 A second embodiment of a conductor arrangement for the device according to the invention for detecting a contact with a manually actuated steering device is shown;

[0041] Figure 3 A third embodiment of a conductor arrangement for a device according to the invention for detecting a contact with a manually actuated steering device is shown; and

[0042] Figure 4 A fourth specific embodiment of a conductor arrangement for a device according to the invention for detecting a contact with a manually actuated steering device is shown. DETAILED DESCRIPTION

[0043] A device for detecting contact with a manually actuated steering device is described below using the example of a vehicle steering wheel.

[0044] According to a first embodiment of the device, in the circumference of the steering wheel, e.g. Figure 1 , a first conductor arrangement 10 is arranged with two parallel-running electrical conductors 12, 14. More precisely, the conductor arrangement 10 is arranged below a decorative surface of the steering wheel, for example below a leather covering.

[0045] The conductor mechanism extends over the entire circumference of the steering wheel rim or at least over a major part thereof. Alternatively, a plurality of such conductor mechanisms 10 are provided, which are respectively arranged in partial regions of the steering wheel rim. In addition, a plurality of conductor mechanisms 10 can be distributed over the annular circumference of the steering wheel rim.

[0046] The two conductors 12 , 14 are provided with insulation, ie they are insulated with respect to one another and with respect to the surroundings.

[0047] The two conductors 12, 14 form a capacitance with one another. In the case of two threads of the same thickness made of the same, well-conducting material, it is possible to calculate the capacitance C as follows:

[0048]

[0049] Where ε: dielectric constant between conductors

[0050] 1: The length of the conductor

[0051] d: distance between the center axes of the conductors

[0052] R: Radius of the conductor cross section

[0053] The first conductor arrangement 10 provided for the device described here is special in that at least one conductor bundle, that is, at least one of the two conductors 12, 14, has a significant ohmic resistance compared to copper wires, in particular in the range of 10Ω / m to 1MΩ / m. The total ohmic resistance or specific resistance of the conductors 12, 14 is known to the control and evaluation device.

[0054] If an alternating voltage, i.e. a voltage having a curve based on oscillation (e.g. sinusoidal oscillation, rectangular oscillation, triangular oscillation or sawtooth oscillation) or a pulse voltage having continuous voltage pulses is applied to the conductor arrangement 10, the total resistance consists of a real part and an imaginary part. The real part is determined by the conductor 12 or 14 having a resistance, while the imaginary part is determined by the capacitance formed between the conductors 12, 14. A certain phase angle is set for the total resistance.

[0055] If the hand now comes very close to the conductor (as is the case when touching the steering wheel rim, for example), the capacitance of the conductor arrangement changes significantly (C 手 ). This means that the imaginary part of the total resistance changes and thus also the phase angle. If the alternating voltage is known, this detuning can be detected and recorded by measuring the current curve. In addition, in the control and analysis device, accurate conclusions about the position of the hand on the steering wheel can be drawn from the change in the real and imaginary part or from the change in the phase angle.

[0056] In this way, not only the contact itself but also the movement patterns (gestures) can be detected within the scope of permanent monitoring by the control and evaluation device. The control and evaluation device can interpret certain gestures and trigger the functions assigned to these gestures.

[0057] If a plurality of conductor arrangements 10 separated from one another are arranged distributed on the steering wheel, a plurality of simultaneous steering wheel contacts (two hands on the steering wheel) can be distinguished.

[0058] The arrangement of (multiple) conductor means 10 is not limited to the steering wheel rim, but can also extend on the spokes and the middle piece of the steering wheel. In addition, any direction of the parallel conductors 12, 14 that is advantageous for analysis, such as a regular or irregular meandering direction, can be provided.

[0059] exist Figure 2 , a second conductor arrangement 10 is shown symbolically, which is provided as a second embodiment of a device for detecting a contact with a manually actuated steering device. The second embodiment is also described below using a vehicle steering wheel as an example.

[0060] The second conductor arrangement 10 is generally composed of a conductor bundle with a plurality of sensing regions 16, which are electrically connected in series. The sensing regions 16 are conductive surfaces or areas, which can be formed, for example, by foils, conductive paints, wire meshes, braided wires or other wire structures. It is essential that the sensing regions 16 are conductive and can generate a significant capacitive field for the hand.

[0061] The electrical conductor 18 between the sensing regions 16 again has an ohmic resistance that is significantly greater than a resistor such as a copper wire, etc. In this case, either the conductor 16 itself can have a resistance, or an electrical component 20, a conductor section, etc. with a significant ohmic resistance can be connected in series.

[0062] As in the first embodiment, the second conductor arrangement 10 is also arranged below the decorative surface of the steering wheel, for example below the leather covering. The conductor arrangement 10 extends over the entire circumference of the steering wheel or at least over a major part. Alternatively, a plurality of such conductor arrangements 10 are provided, which are respectively arranged in partial areas of the steering wheel rim.

[0063] If the hand is very close to the sensing area of ​​the second conductor arrangement 10 (as is the case when touching the steering wheel rim), a capacitance is formed, or capacitance (C 手 ) and the capacitance between the conductor arrangement 10 and the surroundings changes compared to the case without the hand being in close proximity. The presence of the hand then determines or changes the imaginary part of the total resistance of the conductor arrangement 10. A certain phase angle is set depending on the position of the hand. Analogously to the first embodiment, an analysis can be carried out in the control and analysis device by measuring the current curve when the applied alternating voltage is known, which analysis allows accurate conclusions to be drawn about the position of the hand on the steering wheel.

[0064] In the second embodiment, the accuracy (resolution) of the position determination depends inter alia on the number, shape, size and arrangement of the sensing regions 16 .

[0065] In principle, the same contents as in the first embodiment apply to the second embodiment with regard to the arrangement of the second conductor means 10 (steering wheel rim, steering wheel spokes, steering wheel center piece), the arrangement and distribution of a plurality of second conductor means 10 , and gesture recognition.

[0066] The sensing region 16 can be generated and scanned (measured) not only capacitively but also inductively, resistively, digitally (switches), magnetically, optically. Combinations are also possible, for example capacitive-resistive sensing region 16 .

[0067] The scanning of the sensing regions 16 may be performed sequentially or in parallel, wherein the sensing regions 16 may be scanned individually or in groups.

[0068] exist Figure 3 and Figure 4 2 , two further conductor arrangements 10 are shown symbolically, which are provided in a third or fourth embodiment of the device for detecting a contact with a manually actuated steering device.

[0069] exist Figure 3 In the conductor arrangement 10 shown in FIG. 1 , the sensing area 16 is formed by elongated electrical conductors 18, which are tightly bent or twisted in certain areas or have other very significantly bent and different directions from a straight direction. Due to this special direction of the electrical conductors 18, the sensing surface 16 and the (straight) conductor sections with significant ohmic resistance located therebetween and / or with the components 20 (electrical resistor elements, etc.) connected therebetween form individual RC components. These RC components are analyzed one after the other.

[0070] exist Figure 4 The conductor arrangement 10 shown in FIG. Figure 3 However, no resistors in the form of components or the like are inserted between the sensing regions 16. Instead, the known total resistance R of the electrical conductor 18 is taken into account when analyzing the measured current curve in the control and analysis device.

[0071] In all embodiments, different types of contact can be distinguished by suitable analysis algorithms, such as longer contact at a locatable position, tapping motion, stroking motion (including direction), etc. This allows for functions that go beyond the detection of steering wheel contact itself within the scope of safety assistance systems and driver assistance systems and, if necessary, detection of whether the steering wheel is securely gripped. In particular, grip detection can be achieved, i.e., the gripping method of the driver grabbing or holding the steering wheel can be detected.

[0072] By way of example, the most important differentiation possibilities and some of the functions developed with them are listed below again (assuming that the arrangement and design of the conductor arrangement 10 are suitable):

[0073] - generally identify whether the steering wheel is completely gripped by the hands or whether the steering wheel is only touched by fingers in a point-by-point manner, etc.;

[0074] - Recognize point contact (e.g. tapping) → interpret as key pressure;

[0075] - Identify the location of point contact → interpret as different key pressures;

[0076] - Identify the number of simultaneous contacts → conclusions about one-hand or two-hand contact with the steering wheel and / or multi-touch input;

[0077] - Identify the duration of a contact → for infinitely variable adjustment of parameters;

[0078] - Recognize certain gestures → trigger the assigned function, such as setting indicators (left, right), turning on wipers, radio control, usually within the application: "forward", "backward", etc.

[0079] The two described embodiments or certain aspects can naturally also be combined with one another.

[0080] The invention has been explained using the example of a vehicle steering wheel, but is not restricted to this application. The contact recognition according to the invention can in principle be used in any manually actuated steering or control device of a motor vehicle, train, machine or the like.

Claims

1. A device for detecting contact with a manually actuated steering device, the device comprising: Steering device; a conductor arrangement (10) arranged on the deflection device, the conductor arrangement having at least one conductor bundle with a significant ohmic resistance in the range of 10Ω / m to 1MΩ / m; as well as A control and analysis device, the control and analysis device being configured to: - applying an alternating voltage to the conductor means (10); - measuring the current curve in the conductor arrangement (10); - determining the real and imaginary parts of the instantaneous AC resistance of the conductor means (10); and - Analyze the determined values, wherein The conductor arrangement (10) has a plurality of sensing regions (16) in the form of conductive surfaces or conductive areas which are connected in series with one another by electrical conductors (18), wherein the electrical conductors (18) have a significant ohmic resistance between the sensing regions.

2. The device according to claim 1, characterized in that The steering device is a vehicle steering wheel.

3. The device according to claim 1 or 2, characterized in that A plurality of the conductor means (10) are provided and are distributedly arranged on the deflection device.

4. The device according to claim 1 or 2, characterized in that The conductor arrangement (10) is arranged below the surface of the deflection device.

5. The device according to claim 1 or 2, characterized in that The conductor arrangement (10) has two electrical conductors (12, 14) extending substantially in parallel, at least one of the two electrical conductors having a significantly higher apparent ohmic resistance than a copper wire, the apparent ohmic resistance being in the range of 10Ω / m to 1MΩ / m.

6. The device according to claim 5, characterized in that The two electrical conductors (12, 14) are each insulated.

7. The device according to claim 1 or 2, characterized in that The conductor arrangement (10) has one or more elongated electrical conductors (18) with a significant ohmic resistance, which are laid out in a specific manner to form RC components which can be analyzed in turn.

8. The device according to claim 1 or 2, characterized in that The control and analysis means are configured to trigger specific functions depending on the analysis.

9. A method for detecting a touch on a manually actuated steering device by means of a device according to claim 1, the method comprising the following steps: - applying an alternating voltage to at least one conductor arrangement (10), which is arranged on the deflection device and has at least one conductor strand with a significant ohmic resistance in the range of 10Ω / m to 1MΩ / m; - determining the current curve in the conductor arrangement (10); - determining the real and imaginary parts of the instantaneous AC resistance of the conductor means (10); - determining the capacitance or the change in capacitance of the conductor means (10); - determining the phase shift; and - Analyze the determined values.

10. The method according to claim 9, characterized in that The steering device is a vehicle steering wheel.

11. The method according to claim 9, characterized in that The method steps are performed continuously.

12. The method according to any one of claims 9 to 11, characterized in that The analysis comprises at least one of the following steps: - detecting whether the steering device is touched over a large area; - detecting whether the steering device is contacted in a point-wise manner; - Recognize grasp; - Identify the number of simultaneous contacts; - Locate the locations of multiple contacts; - Determine the duration of the contact; -Logo gesture.

13. The method according to claim 12, characterized in that Depending on the analysis, specific functions are triggered.

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